This paper describes the efforts of a private Australian school system to implement practices that facilitate system-wide school effectiveness. The Diocese of Parramatta, a system of 73 primary and secondary Catholic schools, implemented system-level practices that embody elements of Fullan's (1987) notions of support and pressure. The implementation and relationship of five school-development practices are described: school development processes, principal appraisal, professional development for principals, professional development for teachers, and teacher supervision. Pressure is present in the school-development and appraisal processes, and support exists in the form of teacher and professional development, supervision, and provision of consultancy and resources. A systemic framework for school effectiveness has been developed, based on commonly accepted wisdom about the role of the principal, the significance of professional development, and the interdependence of school development, appraisal, and professional development. (LMI)